The present invention relates to using electro-optics for inspecting and determining internal properties and characteristics of a longitudinally moving rod of material, and more particularly, to a method and device for electro-optically inspecting and determining internal properties and characteristics, such as density, structure, defects, and impurities, and variabilities thereof, of a longitudinally moving rod of material. The rod of material is continuously or intermittently moving along its longitudinal axis while at least one focused beam of electromagnetic radiation is incident upon, measurably affected by, and transmitted through, volumetric segments of the longitudinally moving rod of material, along with detecting the transmitted electromagnetic radiation beam, during the electro-optical inspection process of measuring and analyzing the internal properties and characteristics of the longitudinally moving rod of material. The present invention is generally applicable for inspecting and determining internal properties and characteristics of a variety of different types of a rod of material, as long as the rod of material exhibits the behavior that an incident focused beam of electromagnetic radiation, while not altering the rod of material, is affected by and transmittable through volumetric segments of the rod of material. For example, but not limited to, a cigarette rod consisting of processed tobacco inside a rolled and sealed tube of cigarette wrapping paper.
The present invention is particularly applicable to that stage of an overall commercial manufacturing sequence involving continuously transporting or conveying a rod of material between manufacturing processes. There exist overall commercial manufacturing sequences including a stage whereby raw or initially processed material exiting an upstream manufacturing process is formed into a short discrete or long continuous rod of material, which is either wrapped inside a wrapping material or is left unwrapped, and continuously transported or conveyed prior to entering further downstream processes, including for example, a rod cutting process, eventually leading to production of bulk quantities of individually wrapped or unwrapped consumer product. For example, in the case of manufacturing cigarettes, as part of an overall commercial manufacturing sequence, bulk quantities of cut and processed tobacco leaves, along with any number of cigarette tobacco additives or ingredients, exiting an upstream manufacturing process are rolled, wrapped, and sealed, inside cigarette wrapping paper, and continuously transported or conveyed as long, narrow, continuous tobacco filled cylinders or rods prior to entering further downstream processes, including for example, a cigarette rod cutting process, eventually leading to production of bulk quantities of individually cut, wrapped, and non-filtered or filtered, cigarettes in a box.
During such a manufacturing sequence, internal properties and characteristics, such as density, structure, defects, impurities, and variabilities thereof, of the continuously moving rod of material exiting an upstream manufacturing process, may feature values outside of acceptable ranges and/or may undesirably change prior to entering a downstream manufacturing process. At this stage of such a manufacturing sequence, it is critically important that these internal properties and characteristics of the continuously moving rod of material be determined and monitored, such as by employing quality control and quality assurance procedures, and subsequently controlled, such as by employing process control and process feedback procedures, prior to the continuously moving rod of material entering further downstream processes or storage, in order to assure proper characteristics and performance of the finished end products.
In particular, if one or more of the above indicated internal properties and characteristics of a given portion or section of the continuously moving rod of material is outside of established quality control or quality assurance values, use of such portion or section of the rod of material is expected to lead to downstream intermediate products, or stored rod of material, similarly failing their established quality control values, potentially causing undesirable rejection of material, manufacturing down time and added cost to the overall manufacturing sequence. For example, in the case of manufacturing cigarettes, if one or more of the above indicated internal properties and characteristics of a given portion or section of the rod shaped wrapped cigarette tobacco are outside of established quality control values, at least that portion or section of the tobacco filled rod needs to be removed prior to entering further downstream processes or storage, otherwise, ‘below quality’ cigarettes may end up in the consumer marketplace, clearly undesirable to a cigarette manufacturer, as well as undesirable to consumers of cigarettes.
Herein, internal properties and characteristics, such as density, structure, defects, and impurities, and variabilities thereof, of a longitudinally moving rod of material refer to the global, bulk, or macroscopic, internal properties and characteristics, such as density, structure, defects, and impurities, and variabilities thereof, of a specified volumetric segment or number of volumetric segments of the material, including bulk or macroscopic volume occupied by air and moisture throughout the material, making up or forming the longitudinally moving rod of material. These internal properties and characteristics of the longitudinally moving rod are to be clearly distinguished from the local, molecular, or microscopic, properties and characteristics, such as molecular density, molecular structure, microscopic defects, and microscopic impurities, and variabilities thereof, of only the material, excluding bulk or macroscopic volume occupied by air and moisture, making up or forming the longitudinally moving rod of material.
For example, internal properties and characteristics, such as density, structure, defects, and impurities, and variabilities thereof, of a longitudinally moving cigarette rod consisting of processed tobacco inside a rolled and sealed tube of cigarette wrapping paper, refer to the global, bulk, or macroscopic, density, structure, defects, and impurities, and variabilities thereof, of a specified volumetric segment or number of volumetric segments of the processed tobacco, including bulk or macroscopic volume occupied by air and moisture throughout the processed tobacco, inside the rolled and sealed tube of cigarette wrapping paper. These internal properties and characteristics of the longitudinally moving cigarette rod are to be clearly distinguished from the molecular density, molecular structure, microscopic defects, and microscopic impurities, and variabilities thereof, of only the processed tobacco molecules, excluding bulk or macroscopic volume occupied by air and moisture, making up or forming the longitudinally moving cigarette rod.
There is an extensive amount of prior art teachings of methods, devices, and systems, for electro-optically inspecting and determining ‘external’ (and not ‘internal’) properties and characteristics, such as uniformity, structure, color, print, closures, openings, defects (for example, holes, defective and/or missing components), and impurities, and variabilities thereof, of or on the ‘outer or exposed surfaces’ (and not of or in a specified ‘volumetric segment’ or number of ‘volumetric segments’) of a plurality of continuously or intermittently moving rods of material, where the rods of material are continuously or intermittently moving sideways along or rolling around their ‘radial’ axes (and not moving along their ‘longitudinal’ axes) during the actual electro-optical inspection process, as part of a commercial production or manufacturing sequence.
The majority of such prior art is especially with regard to electro-optically inspecting and determining properties and characteristics, such as uniformity, structure, color, print, closures, openings, defects (for example, holes, defective and/or missing components, such as a defective or missing filter), and impurities, of the outer or exposed surface, for example, of the wrapping paper, of the open end, and/or of the filter end, (and not of a specified volumetric segment or number of volumetric segments) of continuously or intermittently moving individually cut and complete cigarettes in their final form prior to packaging, moving sideways along or rolling around their radial axes. Such prior art is based on generating, detecting (collecting and measuring), and analyzing, light ‘reflected by’ (and not transmitted through) the outer or exposed surfaces of the continuously or intermittently moving rods of material. Such prior art may be divided into two main categories, according to the type of optics, electronics, and/or electro-optics, employed during the electro-optical inspection.
In the first main category, electro-optical inspecting is performed by generating, detecting (collecting and measuring), and analyzing, light reflected by the outer or exposed surface of at least a part of each rod of material, in the form of light beams or rays and intensities thereof. Selected examples of this main category of prior art, especially as applied to electro-optically inspecting the outer or exposed surface of at least a part of individual completed cigarettes, are the disclosures of U.S. Pat. No. 3,980,567 to Benini; U.S. Pat. No. 4,090,794 to Benini; and U.S. Pat. No. 4,639,592 to Heitmann.
In the second main category, electro-optical inspecting is performed by generating, detecting (collecting and measuring), and analyzing, light reflected by the outer or exposed surface of at least a part of each rod of material, in the form of photographic or video camera images. Selected examples of this main category of prior art, especially as applied to electro-optically inspecting the outer or exposed surface of at least a part of individual completed cigarettes, are the disclosures of U.S. Pat. No. 5,013,905 to Neri; U.S. Pat. No. 5,228,462 to Osmalov et al.; U.S. Pat. No. 5,432,600 to Grollimund et al.; and U.S. Pat. No. 5,448,365 to Grollimund et al.
The present invention is directed to commercial applications requiring real time, non-invasive, high speed, high sensitivity, low noise, high accuracy, high precision, temperature compensative, and low vibration, measuring and analyzing internal properties and characteristics, such as density, structure, defects, and impurities, and variabilities thereof, of a specified volumetric segment or number of volumetric segments, of a rod of material, such as a cigarette rod, continuously or intermittently moving along its longitudinal axis, as the rod of material is transported or conveyed during a commercial manufacturing sequence, particularly a manufacturing sequence including quality control and/or quality assurance processes.
Accordingly, each of the above cited prior art, and similar prior art, feature at least two significant and fundamental differences, and associated limitations thereof, with regard to the intended scope and applications of the present invention.
The first significant and fundamental difference is that such prior art teaches about electro-optically inspecting and determining only ‘external’ properties and characteristics, such as uniformity, structure, color, print, closure, defects, and impurities, and variabilities thereof, of the outer or exposed surfaces of a plurality of continuously or intermittently moving rods of material. Accordingly, such prior art teachings are solely based on generating, detecting (collecting and measuring), and analyzing, light ‘reflected by’, and not ‘transmitted through’, the outer or exposed surfaces of the continuously or intermittently moving rods of material. Such prior art teachings are not obviously extendable and/or applicable for generating, detecting (collecting and measuring), and analyzing, light transmitted through the outer or exposed surfaces of the moving rods of material, and therefore, are not obviously extendable and/or applicable for electro-optically measuring and analyzing ‘internal’ properties and characteristics, such as density, structure, defects, and impurities, and variabilities thereof, of a specified volumetric segment or number of volumetric segments of the material making up or forming a longitudinally moving rod of material, according to the intended scope and applications of the present invention.
The second significant and fundamental difference is that such prior art teaches about electro-optically inspecting and determining the external properties and characteristics of the outer or exposed surfaces of continuously or intermittently moving rods of material, where the rods of material are specifically restricted to moving sideways along or rolling around their ‘radial’ axes, and not moving along their ‘longitudinal’ axes, during the actual electro-optical inspection, as the rods of material are transported or conveyed during a manufacturing process. Therein is no teaching about performing the electro-optical inspection while the rods of material are moving along their longitudinal axes, during the real time electro-optical inspection, as the rods of material are transported or conveyed during a manufacturing sequence. There are commercial manufacturing sequences which either require, or where it would be highly desirable and advantageous, having a rod of material moving along its longitudinal axis, as the rod of material is transported or conveyed during the manufacturing sequence.
There are prior art teachings about electro-optically inspecting a longitudinally moving rod of material, as the rod of material is transported or conveyed during a commercial manufacturing sequence. Such prior art, particularly applicable to the cigarette manufacturing industry, selections of which are briefly described herein below, is also fundamentally different from, and features significant limitations with respect to, the intended scope and applications of the present invention.
In the disclosures of U.S. Pat. No. 6,213,128 B1, and U.S. Patent Application No. 2001/0001390 A1, both to Smith et al., there are described a method and apparatus for making and electro-optically inspecting a multi-component cigarette. As for the above previously cited prior art, the electro-optical inspection is based on generating, detecting (collecting and measuring), and analyzing, light ‘reflected by’, and not ‘transmitted through’, the outer or exposed surfaces of a variety of cigarette components, such as cigarette tobacco rods, filters, tubes, and chambers, in the form of camera images, as these cigarette components are longitudinally resting or positioned on open cigarette wrapping paper which is continuously moving along its longitudinal axis and transported or conveyed during the manufacturing sequence.
In the disclosures of U.S. Pat. No. 3,854,587; its reissue, Re. 29,839; and its improvement, U.S. Pat. No. 4,208,578, each to McLoughlin et al., there are described an “(electro-)optical inspection apparatus for monitoring a continuously (longitudinally) moving rod (in particular, a cigarette rod), comprising a circular head through which the rod passes (along its longitudinal axis), a first set of fiber optic conductors which transmits light from a source to the head to illuminate the rod, and a second set of fiber optic conductors which pick up light reflected from (and not transmitted through) the rod passing through the head and transmits the reflected light to a number of photoelectric elements. The second set of conductors are divided into angularly spaced groups around the head and adjacent groups lead to separate photoelectric elements”. Outputs of the photoelectric elements are processed and analyzed by logic circuitry for determining the presence of a fault in the inspected rod, and if found, causes a fault signal to actuate a rejection mechanism when the part of the rod at which the fault has been sensed reaches a rejection point.
In the disclosure of U.S. Pat. No. 4,377,743 to Bolt et al., there is described a device and corresponding method for electro-optically inspecting a longitudinally moving rod (in particular, a cigarette rod), wherein the device comprises “a plurality of focused light emitter-detector units spaced circumferentially around a rod being inspected, each unit being arranged to propagate focused light onto a defined surface region of the rod and to receive the light reflected from (and not transmitted by) that surface region and further arranged to generate an electrical signal related to the intensity of the received light. Two, or more, axially displaced arrays of units are each arranged to inspect areas of the rod which are staggered in relation to the areas inspected by the other array or arrays”.
In the Bolt et al. invention, “the measuring head of the apparatus comprises a plurality of infra-red sensor units, which each contain a light emitting diode and a phototransistor, positioned behind respective lenses. The lens for the light emitting diode focuses light onto a specific area of the cigarette rod and the lens for the phototransistor collects the light reflected from that area, i.e., “focuses” the reflected light onto the phototransistor”. Outputs of the phototransistors are processed and analyzed for determining the presence of a fault in the inspected cigarette rod, and if found, causes a fault signal to actuate a cigarette ejection mechanism. The invention includes “means (a transparent tube) for guiding the continuous cigarette rod (along its longitudinal axis) along a predetermined path extending through an (electro-optical) inspection station”.
In the disclosure of U.S. Pat. No. 4,645,921 to Heitmann et al., there is described an “Apparatus for optically scanning a (longitudinally) moving cigarette rod (a plurality of discrete, coaxial complete cigarettes, long continuous cigarette rods, filter rod sections, and the like) for the presence of defects in its external surface (and not internal volume) which has two annularly arranged groups of diodes which emit green light in the wavelength range of between 0.49 and 0.58.mu. and direct such light from the opposite sides of a plane that is normal to the (longitudinally) moving rod so that the incident light is reflected (and not transmitted) by successive annular portions of the external surface of the rod into the aforementioned plane. The reflected light is focused by systems of lenses upon discrete photosensitive transducers through discrete slit diaphragms on the transducers themselves or on a thin metallic ring which is adjustably mounted on the support for the diodes and the systems of lenses”. The disclosed invention is “especially for scanning the circumferentially complete annular external surfaces of a series of coaxial cigarettes”.
Although the prior art disclosures of Smith et al., McLoughlin et al., Bolt et al., and Heitmann et al., teach about electro-optically inspecting a longitudinally moving rod of material, such prior art teachings are solely based on generating, detecting (collecting and measuring), and analyzing, light ‘reflected by’ the outer or exposed surfaces of the moving rods of material, and are not obviously extendable and/or applicable for generating, detecting (collecting and measuring), and analyzing, light ‘transmitted through’ the outer or exposed surfaces of the moving rods of material. Accordingly, such prior art teachings are not obviously extendable and/or applicable for electro-optically measuring and analyzing ‘internal’ properties and characteristics, such as density, structure, defects, and impurities, and variabilities thereof, of a specified volumetric segment or number of volumetric segments of the material making up or forming a longitudinally moving rod of material, according to the intended scope and applications of the present invention.
In addition to the above described fundamental difference, a significant limitation existing in the prior art of electro-optically inspecting a longitudinally moving rod of material, regards the undesirable affect that temperature changes may have on accuracy and precision of the results obtained from the electro-optical inspection process. While electro-optically inspecting a longitudinally moving rod of material, temperature changes typically occur in critical regions of operation of the electro-optical inspection apparatus. Such critical regions of operation are particularly in the immediate vicinity of the electro-optically inspected section of the moving rod of material. Magnitudes of such temperature changes may be sufficiently large so as to significantly increase noise and error levels during the illumination and detection processes, which may translate to meaningful decreases in accuracy and precision of the results obtained from the electro-optical inspection process.
The prior art disclosures of Smith et al., McLoughlin et al., Bolt et al., and Heitmann et al., include no explicit or suggestive teaching of a procedure or of equipment for monitoring, and/or compensating for, temperature changes, in the critical region of operation of the electro-optical inspection apparatus.
Another significant limitation existing in the prior art of electro-optically inspecting a longitudinally moving rod of material, regards the undesirable affect that radially directed vibrating of the longitudinally moving rod of material, in general, and of the electro-optically inspected section of the longitudinally moving rod of material, in particular, during the electro-optical inspection process, may have on accuracy and precision of the results obtained from the electro-optical inspection process. While electro-optically inspecting a longitudinally moving rod of material, the longitudinally moving rod of material, in general, and the electro-optically inspected section of the longitudinally moving rod of material, in particular, typically vibrates, particularly, in the radial direction. Magnitudes of such radially directed vibrating may be sufficiently large so as to significantly increase noise and error levels during the illumination and detection processes, which may translate to meaningful decreases in accuracy and precision of the results obtained from the electro-optical inspection process.
The prior art disclosures of Smith et al., McLoughlin et al., Bolt et al., and Heitmann et al., include no explicit or suggestive teaching of a procedure or of equipment for preventing, eliminating, or reducing, radially directed vibrating of the longitudinally moving rod of material, in general, and of the electro-optically inspected section of the longitudinally moving rod of material, in particular, during the electro-optical inspection process.
In general, procedures and equipment for monitoring temperature and/or compensating operation of a process for temperature changes, as well as procedures and/or equipment for preventing, eliminating, or reducing, radially directed vibrating of a longitudinally moving object during operation of a process, are known and widely applicable, including on a commercial or manufacturing scale, and are well taught about. A possible reason for absence of such teachings specifically in the prior art of electro-optically inspecting a longitudinally moving rod of material, for example, as taught about in the disclosures of Smith et al., McLoughlin et al., Bolt et al., and Heitmann et al., is that the disclosed electro-optical inspection methods and apparatuses, solely based on generating, detecting (collecting and measuring), and analyzing, light reflected by the outer or exposed surfaces of the longitudinally moving rods of material, are insufficiently sensitive to be significantly affected by the above described types of local temperature changes and/or radially directed vibrating. This, therefore, precludes a need for monitoring temperature and/or compensating for such local temperature changes, or, for preventing, eliminating, or reducing, such radially directed vibrating, of the longitudinally moving rod of material during the electro-optical inspection process.
Moreover, due to physical and/or electromechanical limitations, especially regarding design, construction, and operation, of the illumination and detection units in the electro-optical inspection apparatuses taught about in McLoughlin et al., Bolt et al., and Heitmann et al., involving a plurality of miniaturized electro-optical components (in particular, light generating, conducting, emitting, and receiving, types of devices, mechanisms, components, and elements, such as LEDs, lenses, phototransistors, photosensitive transducers, fiber optic conductors or guides, and photoelectric elements) tightly configured and oriented within limited spaces, inclusion of a temperature monitoring and/or compensation procedure and equipment, and/or inclusion of a vibrating prevention, reduction, and/or compensation, procedure and equipment, operative during the electro-optical inspection process, is not readily accomplishable.
Accordingly, each of the above cited prior art, and similar prior art, feature several significant and fundamental limitations, and associated limitations thereof, with regard to the intended scope and applications of the present invention for electro-optically inspecting and determining internal properties and characteristics of a longitudinally moving rod of material.
To one of ordinary skill in the art, there is thus a need for, and it would be highly advantageous to have a method and device for electro-optically inspecting and determining internal properties and characteristics, such as density, structure, defects, and impurities, and variabilities thereof, of a longitudinally moving rod of material. Moreover, there is a need for such an invention wherein the rod of material is continuously or intermittently moving along its longitudinal axis during the electro-optical inspection process of measuring and analyzing the internal properties and characteristics of a specified volumetric segment or number of volumetric segments of the longitudinally moving rod of material.
There is also a need for such an invention which is directed to commercial applications requiring real time, non-invasive, high speed, high sensitivity, low noise, high accuracy, high precision, temperature compensative, and low vibration, measuring and analyzing of internal properties and characteristics of a longitudinally moving rod of material, as the rod of material is transported or conveyed during a commercial manufacturing sequence, particularly a manufacturing sequence including quality control and/or quality assurance processes. There is also a need for such an invention which is generally applicable for inspecting and determining internal properties and characteristics of a variety of different types of a rod of material, for example, but not limited to, a cigarette rod.